Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755333AbbKESse (ORCPT ); Thu, 5 Nov 2015 13:48:34 -0500 Received: from www.linutronix.de ([62.245.132.108]:56852 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750800AbbKESsd (ORCPT ); Thu, 5 Nov 2015 13:48:33 -0500 Date: Thu, 5 Nov 2015 19:47:46 +0100 (CET) From: Thomas Gleixner To: Arjan van de Ven cc: Peter Zijlstra , Jacob Pan , LKML , Paul Turner , Len Brown , Srinivas Pandruvada , Tim Chen , Andi Kleen , Rafael Wysocki Subject: Re: [RFC PATCH 3/3] sched: introduce synchronized idle injection In-Reply-To: <563B75B2.3040503@linux.intel.com> Message-ID: References: <1446509428-5616-1-git-send-email-jacob.jun.pan@linux.intel.com> <1446509428-5616-4-git-send-email-jacob.jun.pan@linux.intel.com> <20151103133120.GD17308@twins.programming.kicks-ass.net> <20151103084501.289ec5d1@yairi> <20151105100922.GA3604@twins.programming.kicks-ass.net> <563B6642.2090803@linux.intel.com> <20151105143332.GQ17308@twins.programming.kicks-ass.net> <563B75B2.3040503@linux.intel.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 958 Lines: 24 On Thu, 5 Nov 2015, Arjan van de Ven wrote: > On 11/5/2015 6:33 AM, Peter Zijlstra wrote: > > > It just grates at me a bit that we have to touch hot paths for such > scenarios :/ > > well we have this as a driver right now that does not touch hot paths, > but it seems you and tglx also hate that approach with a passion.... Right. It's a horror to deal with tasks which try to impersonate idle while actually running as highest priority task in the system. We really want the scheduler to know about it. Yes, we probably have to pay the price for some extra check in the hot path, but that's way more sensible than figuring out how 'want to be idle' RT tasks wreckage the world and some more. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/